The typical motor control system where the motor is to be controlled in some variable such as speed, voltage or current is a control system wherein there is one control circuit for each individual motor to be controlled. This results in a relatively high proportion of the total cost being due to the control circuit. A prior art attempt at an energization system wherein there was a thyristor control of individual motors supplied from a common power supply, required the complexity of superimposing a high-frequency control signal onto the commercially available power frequency on the two bus conductors. This required the complexity of high-frequency control signals in addition to supplying AC on the bus conductors rather than DC. The prior art has proposed use of variable speed DC motors operable from a voltage rectified from an AC source and controllable by means such as saturable reactors. However, in such systems plural motor loads were not able to be controlled individually, and at no time was there a net negative voltage applied on the normally positive bus conductors. Still another prior art motor control circuit took into account the counter e.m.f. and compared this counter e.m.f. with a trigger voltage, yet such circuit did not take into account what might happen if no counter e.m.f. was developed. Still other motor control circuits have utilized DC motors which are adjustable in speed and which are supplied from two separate voltage sources connected generally in opposition for control purposes, yet they did not provide a periodically changed voltage on the bus conductors nor did they provide for controlling the speed individually of different loads.